DevOps (a clipped compound of "development" and "operations") is a software development and delivery process that emphasizes communication and collaboration between product management, software development, and operations professionals. It seeks to automate the process of software integration, testing, deployment, and infrastructure changes by establishing a culture and environment where building, testing, and releasing software can happen rapidly, frequently, and more reliably.
In traditional, functionally-separated organizations, there is rarely a cross-departmental integration of these functions with IT operations. DevOps promotes a set of processes and methods for thinking about communication and collaboration - between departments of development, QA (quality assurance), and IT operations. In some organizations, this collaboration extends to embedding IT operations specialists within cross-functional software development teams and may involve matrix management.
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History
Site Reliability Engineering was a team created at Google around 2003 to run their production environment. The team was tasked to make Google's sites run smoothly, efficiently and more reliably. Early on, Google's large-scale systems required the company to come up with new paradigms on how to manage such large systems that have never existed before and at the same time introduce new features continuously but at a very high-quality end user experience. The SRE processes that have been honed over the years are being used by other, mainly large scale, companies that are also starting to implement this paradigm.
At the Agile 2008 conference, Andrew Shafer and Patrick Debois presented on "Agile Infrastructure". The term DevOps was popularized through a series of "devopsdays" starting in 2009 in Belgium. Since then, there have been devopsdays conferences, held in many countries, worldwide.
The popularity of DevOps has grown in recent years, inspiring many other tangential initiatives including OpsDev, WinOps, and BizDevOps.
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DevOps toolchain
As DevOps is a truly cross-functional mode of working, there is no single "DevOps tool": it is rather a set (or "toolchain") of multiple tools. DevOps tools end to fit into one or more of these categories, reflective of key aspects of the development and delivery process:
- Code -- code development and review, source code management tools, code merging
- Build -- continuous integration tools, build status
- Test -- continuous testing tools that provide feedback on business risks
- Package -- artifact repository, application pre-deployment staging
- Release -- change management, release approvals, release automation
- Configure -- infrastructure configuration and management, Infrastructure as Code tools
- Monitor -- applications performance monitoring, end-user experience
While there are many tools available, certain categories are essential in a DevOps toolchain; especially containerization (e.g. Docker), continuous integration (e.g. Jenkins), infrastructure as code (e.g. Puppet) and platform virtualization (e.g. Vagrant).
Containerization
Docker is a software technology providing containers, promoted by the company Docker, Inc. Docker provides an additional layer of abstraction and automation of operating-system-level virtualization on Windows and Linux. Docker uses the resource isolation features of the Linux kernel such as cgroups and kernel namespaces, and a union-capable file system such as OverlayFS and others to allow independent "containers" to run within a single Linux instance, avoiding the overhead of starting and maintaining virtual machines.
Examples of systems for managing the deployment of containers include Kubernetes and Apache Mesos.
Relationship to agile and continuous delivery
Agile
The need for DevOps arose from the increasing success of agile software development, as that led to organizations wanting to release their software faster and more frequently. They sought to overcome the strain this put on their release management processes, by adopting patterns such as application release automation, continuous integration tools, and continuous delivery.
Continuous delivery
Continuous delivery and DevOps have common goals and are often used in conjunction, but there are subtle differences.
While continuous delivery is focused on automating the processes in software delivery, DevOps also focuses on the organization change to support great collaboration between the many functions involved.
DevOps and continuous delivery share a background in agile methods and lean thinking: small and quick changes with focused value to the end customer. They are well communicated and collaborated internally, thus helping achieve quick time to market, with reduced risks.
Goals
The goals of DevOps span the entire delivery pipeline. They include:
- Improved deployment frequency;
- Faster time to market;
- Lower failure rate of new releases;
- Shortened lead time between fixes;
- Faster mean time to recovery (in the event of a new release crashing or otherwise disabling the current system).
Simple processes become increasingly programmable and dynamic, using a DevOps approach. DevOps aims to maximize the predictability, efficiency, security, and maintainability of operational processes. Very often, automation supports this objective.
DevOps integration targets product delivery, continuous testing, quality testing, feature development, and maintenance releases in order to improve reliability and security and provide faster development and deployment cycles. Many of the ideas (and people) involved in DevOps came from the enterprise systems management and agile software development movements.
DevOps aids in software application release management for an organization, by standardizing development environments. Events can be more easily tracked, as well as resolving documented process control and granular reporting issues. The DevOps approach grants developers more control of the environment, giving infrastructure more application-centric understanding.
Cultural change
DevOps is more than just a tool or a process change; it inherently requires an organizational culture shift. This cultural change is especially difficult, because of the conflicting nature of departmental roles:
- Operations -- seeks organizational stability
- Developers -- seek change
- Testers -- seek risk reduction
Getting these groups to work cohesively is a critical challenge in enterprise DevOps adoption.
While DevOps reflects complex topics, the DevOps community uses memes to communicate important concepts, much like "The Cathedral and the Bazaar" from the open source community. Examples of DevOps memes include:
- Cattle & Pets: the paradigm of disposable server infrastructure.
- 10 deployments per day: the story of Flickr adopting DevOps.
- Matrix: "what if I told you that DevOps and Agile are not the same".
Building a DevOps culture
DevOps principles demand strong interdepartmental communication--team-building and other employee engagement activities are often used--to create an environment that fosters this communication and cultural change, within an organization. Team-building activities can include board games, trust activities, and employee engagement seminars.
Deployment
Companies with very frequent releases may require a DevOps awareness or orientation program. For example, the company that operates the image hosting website Flickr developed a DevOps approach, to support a business requirement of ten deployments per day; this daily deployment cycle would be much higher at organizations producing multi-focus or multi-function applications. This is referred to as continuous deployment or continuous delivery and has been associated with the lean startup methodology. Working groups, professional associations and blogs have formed on the topic since 2009.
DevOps and architecture
To practice DevOps effectively, software applications have to meet a set of architecturally significant requirements (ASRs), such as: deployability, modifiability, testability, and monitorability. These ASRs require a high priority and cannot be traded off lightly.
Although in principle it is possible to practice DevOps with any architectural style -- the microservices architectural style is becoming the standard for building continuously deployed systems. Because the size of each service is small, it allows the architecture of an individual service to emerge through continuous refactoring, hence reducing the need for a big upfront design and allows for releasing the software early and continuously.
Scope of adoption
Some articles in the DevOps literature assume, or recommend, significant participation in DevOps initiatives from outside an organization's IT department, e.g.: "DevOps is just the agile principle, taken to the full enterprise."
A survey published in January 2016 by the SaaS cloud-computing company RightScale, DevOps adoption increased from 66 percent in 2015 to 74 percent in 2016. And among larger enterprise organizations, DevOps adoption is even higher -- 81 percent.
Adoption of DevOps is being driven by many factors -- including:
- Use of agile and other development processes and methods;
- Demand for an increased rate of production releases -- from application and business unit stakeholders;
- Wide availability of virtualized and cloud infrastructure -- from internal and external providers;
- Increased usage of data center automation and configuration management tools;
- Increased focus on test automation and continuous integration methods;
- A critical mass of publicly-available best practices.
Incremental adoption
The theory of constraints (ToC) applies to the adoption of DevOps: the limiting constraint is often the ingrained aversion to change from departments within the enterprise. Incremental adoption embodies the methodology that the theory of constraints provides for combating any constraint, known as the "five focusing steps".
The incremental approach centers around the idea of minimizing risk and cost of a DevOps adoption whilst building the necessary in-house skillset and momentum needed to have widespread successful implementation across the enterprise. Gene Kim's "Three Ways Principles" essentially establishes different ways of incremental DevOps adoption:
The first way: systems thinking
The emphasis is on the performance of the entire system, as opposed to the performance of a specific or single department or individual. Focus is also on all business value streams that are enabled by IT. A key aspect of this approach is ensuring that known defects are never passed along, e.g., from QA to operations.
The second way: amplified feedback loops
The emphasis is on increasing feedback and understanding of all teams involved. The outcomes of this will be: increased communication and responding to all customers (internal and external), shortening and amplifying all feedback loops, and embedding knowledge where and to whom it's needed.
The third way: culture of continual experimentation and learning
Two things are equally important: experimentation and practice. Embedding this in the working culture--where learning from taking risks, and repetition and practice are encouraged--is key to mastery. Risk taking and experimentation--promoting improvement and mastery--provides the skills, required to revert any mistakes.
Platforms
DevOps was originally used by teams running software on a Linux tech stack.
WinOps (a portmanteau of "Windows" and "DevOps") is a term used referring to the cultural movement of DevOps practices for a Microsoft-centric view. It emphasizes the use of the cloud, automation and integrating development and IT operations into one fluid method on the Windows platform. As an amalgamation of Windows and DevOps, the term represents the new emphasis on using existing DevOps methodologies in the traditionally less open-source Microsoft space.
Source of the article : Wikipedia
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